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CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

CWE-338 Medium

  • Abstraction:
  • Base
  • Structure:
  • Simple
  • Status:
  • Draft
Weakness Name

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Description

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks. Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.

Common Consequences

Scope: Access Control

Impact: Bypass Protection Mechanism

Notes: If a PRNG is used for authentication and authorization, such as a session ID or a seed for generating a cryptographic key, then an attacker may be able to easily guess the ID or cryptographic key and gain access to restricted functionality.

Related Weaknesses
  • Release Date:
  • 2006-07-19
  • Latest Modification Date:
  • 2023-10-26

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